Method and system for displaying video signals

ABSTRACT

A method and system for notifying a viewer of the arrival or presence of one or more video input signals in a video display system, such as a personal computer (PC) or television (TV) system. If a video signal is already present, the system may optionally notify a viewer of the termination or absence of the video signal. The invention further provides the viewer with the opportunity to dynamically select the video source to view. Upon sensing the presence of a new video signal, the system alerts the viewer who may then select whether to view the new video signal or maintain prior viewing status.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the management of video displaysystems, such as computer monitors. More particularly, the inventionrelates to the selection of video signals in a video system havingmultiple inputs.

2. Description of the Related Art

In recent years, the use of multimedia applications has steadily spreadto many fields of technology. The term “multimedia” commonly refers tothe fusion of information, communications, and visual media in a singleprocessing system. With the evolution of the public Internet, severalcomputer-based systems now offer multimedia applications for thecommunication and processing of data, voice, image/graphics, and video.Additionally, there are several television-based systems currently inuse and development, such as interactive television (TV) or Web TV,which also support multimedia applications. The interactive TV conceptcombines the Internet and TV to enable viewers to access additionalinformation about the programs they are watching and act on it throughthe Internet. The interactive TV experience may occur on a personalcomputer (PC) with a tuner card, such as those used with Intel'sIntercast Technology. Alternatively, interactive TV may also be based ona standard television set with an external device supporting interactiveaccess.

There are at least two types of display systems available today: one forPC systems, and another for TV systems. The PC display system typicallyincludes a display unit, processing circuit, and display adapter. Thedisplay adapter is a device which transforms text, graphics, or videosignals from digital form to analog form for display by the displayunit. The display unit may be a cathode ray tube (CRT) or liquid crystaldisplay (LCD) device capable of displaying text, graphics, or video. Onthe other hand, the TV display system typically includes a monitor,demodulator, and tuner. The tuner and demodulator supply one or morevideo signals for display by the monitor.

A variety of video standards are used in connection with PC systems,including MDA, CGA, HGC, EGA, PGA, VGA, MCGA, Super VGA, 8514/A, andXGA. In the case of TV systems, a different variety of video standardsare used including National Television System Committee (NTSC), PhaseAlternating Line (PAL), and Systeme Electronique Couleur Avec Memoire(SECAM).

As PC and TV systems merge closer together, there is a heightened needto support multiple video inputs to accommodate for a variety of videosignals and formats. Moreover, accommodating for multiple video inputsmay be required when receiving video signals from dedicated multiplevideo sources, even though the video signals may be in the same format.When receiving video signals from multiple video sources at the sametime (i.e., concurrently), a user has to manually select one videosource to override one or more other video sources. For example, when acable TV signal and a video cassette recorder (VCR) signal are receivedconcurrently, a TV user must press one or more control buttons to selectwhich of the two video signals to display on the TV monitor. In a PCsystem, a PC user may alternatively instruct the PC (e.g., byspecialized programming) to prioritize video input sources in case ofconcurrent arrival of multiple video signals. Once the user selects aparticular video source, the user may not view video signals from othervideo sources. To view video signals from other sources, the user has tore-press control buttons or reprogram specialized instructions. Moreparticularly, the user is unable to accommodate for recognizing arrival(i.e., new presence) or termination (i.e., new absence) of other videosignals into and from the PC or TV system.

Therefore, there is a need in video display technology to accommodatefor concurrent presence of multiple video signals in a PC or TVenvironment. The new system and method should enable a user todynamically select multiple video sources as the user desires.

SUMMARY OF THE INVENTION

To overcome the above-mentioned problems, the invention provides a videosystem which displays at least one video signal to a user. In oneembodiment, the system comprises a detection circuit which detects anactivity related to the at least one video signal. The detection circuitcommunicates information about the activity for processing. The systemfurther comprises a processing circuit, electrically coupled to thedetection circuit, which receives the information about the activityfrom the detection circuit. The detection circuit notifies the user ofthe activity related to the at least one video signal. In anotherembodiment, the system comprises a detection circuit which detectsarrival of the at least one video signal, and communicates at least oneinterrupt signal for processing. The system further comprises aprocessor, electrically coupled to the detection circuit, which receivesthe interrupt signal. The processor determines which of the at least onevideo signal has arrived, and notifies the user to select one of the atleast one video signal for display.

The invention further provides a method of displaying at least one videosignal to a user. The method comprises the acts of detecting an activityof the at least one video signal, and communicating information aboutthe activity to a processor. The method further comprises the acts ofnotifying the user of the activity, and selecting one of the at leastone video signal for display. In another embodiment, the inventionprovides a program storage device storing instructions that whenexecuted by a computer perform a method of displaying at least one videosignal to a user. The method comprises the acts of detecting an activityof the at least one video signal, and communicating information aboutthe activity to a processor. The method further comprises the acts ofnotifying the user of the activity, and selecting one of the at leastone video signal for display.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the inventionwill be better understood by referring to the following detaileddescription, which should be read in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a block diagram of an exemplary video system having multiplevideo inputs.

FIG. 2 is a block diagram of one embodiment of the video system of theinvention.

FIG. 3 is a flowchart describing the steps executed by the video systemof FIG. 2.

FIG. 4 is a block diagram of one embodiment of the video detect circuitof the video system of FIG. 2.

FIG. 5 is an exemplary screen display indicating the presence of one ormore video signals in the video system of FIG. 2.

FIG. 6 is an exemplary screen display of a control panel of the videosystem of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

To better understand the invention, a brief description of functionalcomponents of an exemplary video system is first provided. FIG. 1 is ablock diagram of an exemplary video system 100 having multiple videoinputs. A multiplexer (MUX) 110 receives one or more video input signals(VIS) 104 from one or more video sources (not shown in this figure). TheMUX 110 may receive the VIS 104 over copper, fiber-optic, or air mediausing an appropriate receiver. The MUX 110 may employ any method ofcoordinating the transfer of concurrent multiple input signals into asingle output. For instance, the MUX 110 may comprise an electronicswitch which allows connection of a predetermined VIS 104 to the outputof the MUX 110. Alternatively, in more sophisticated systems, the MUX110 may employ multiplexing techniques such as time divisionmultiplexing (TDM), frequency division multiplexing (FDM), or othersimilar methods which are known in the art. In case of analog video, theVIS 104 may be in any transmittable video format, such as NTSC, PAL, orSECAM. In case of digital video, the video format of VIS 104 may be in aserial digital interconnect (SDI), serial digital data interconnect(SDDI), Fiber Channel (FC), synchronous digital hierarchy (SDH), orother video formats which are known in the art. In addition to radiofrequency (RF) channel medium (e.g., cable, satellite, or VHF/UHF),unconventional transmission methods such as the Internet and/orasynchronous transfer mode (ATM) media may be predominant methods oftransmission for all kinds of video signal formats.

To accommodate for the transmission of video signals over suchunconventional transmission media, video information may be compressedusing any of a variety of compression techniques which are known in theart. One example of such a compression technique may comply with amotion picture expert group (MPEG) standard. MPEG is an internationalstandard which defines the display of video at 25 images per secondhaving a transmission rate of 150-300 Kbytes per second. MPEG allows thedisplay of full screen and full motion video with CD sound quality usingrelatively little memory. MPEG-1 is another set of internationalstandards for the compression and decompression of digital videosignals. MPEG-1 specifies a video resolution of 352×240 pixelscompressed at a rate of 30/25 frames per second over a bandwidth of 150Kbytes per second. MPEG-2 is yet another standard which specifies avideo resolution of 720×480 pixels over a bandwidth ranging from 0.5 tomore than 2 Mbytes per second. In general, MPEG-2 may be used for highdefinition television (HDTV) and digital versatile disk (DVD) drives.DVD is an optical disk having a capacity of up to 17 Gbytes whichcontain full-length motion pictures for viewing on a PC.

If necessary and, particularly, when the VIS 104 is compressed prior toinitial transmission, the video system 100 may employ an MPEG decoder114 to decompress the VIS 104 for processing. In case of analog TVsystems, a digital-to-analog converter (DAC) 120 may be required toconvert the VIS 104 from digital to analog form. For instance, the DAC120 may convert SDI signals into NTSC format for further processing. Asnoted above, a tuner 124 and a demodulator 128 may be used to supply aTV monitor 130 with the appropriate video signal for display by themonitor 130. In case of digital TV systems (e.g., HDTV), the HDTV mayemploy appropriate processing circuitry to display digital VIS 104 by aHDTV monitor.

In case of PC systems, a large amount video information may becommunicated among a video card, a video processor (e.g., CPU), and asystem memory over a video interface. A video interface may be definedas the medium by which a video processor and memory communicate with therest of the PC. The video interface may comprise a local bus 134, whichmay be an industry standard architecture (ISA), VESA local (VLB),peripheral component interconnect (PCI), an accelerated graphics port(AGP), or other similar video bus which is known in the art. As notedabove, a display adapter 140 (e.g., a video card) may be used totransform text, graphics, or video signals from digital form to analogform for display by a PC monitor 150. The PC monitor 150 may be acathode ray tube (CRT) or liquid crystal display (LCD), or any otherdevice which is capable of displaying text, graphics, or video.

FIG. 2 is a block diagram of one embodiment of the video system of theinvention. The video system 200 may comprise an analog or digital videosystem which is based on a TV or PC system architecture. A multiplexer(MUX) 210 may receive one or more video input signals (VIS) 204 forprocessing. Depending on its multiplexing technique, the MUX 210communicates one of the VIS 204 to a multimedia processing circuit (MPC)220 which may include some or all of the functional blocks illustratedin the video system 100 of FIG. 1. The MPC 220 may also include aprocessor configured to be programmed with instructions to perform orcause performance of video signal processing functions described above.Such a processor may be adapted for video signal processing, such asthose used in PC or digital TV systems. An example of such a processormay be the Mpact media processor by Chromatic Research, Inc.

Moreover, the video system 200 comprises one or more video detectcircuits (VDC) 230 which monitors the activity of the VIS 204 ports. Asused herein, the term “activity” refers to any signal activityassociated with or related to video signals (i.e., VIS 204) including,without limitation, arrival, presence, termination, or absence of theVIS 204 at its respective port. The VDC 230 monitors the presence andabsence of VIS 204 signals arriving into the video systems 200. Each VDC230 is electrically coupled to its respective VIS 204. In thisembodiment, three VIS 204 and three respective VDC 230 are depicted inFIG. 2. However, depending on the desired application, the video system200 may employ any number of VIS 204 and VDC 230. Moreover, in thisembodiment, one VDC 230 monitors one VIS 204. However, several VDC 230may be implemented as one video detect unit to monitor one or more VIS204. Finally a general processor input/output (GPIO) 240 communicateswith the one or more VDC 230 to monitor and reset each VDC 230 after itdetects a VIS 204. The GPIO 240 may be a 37M707 processor manufacturedby SMC.

Upon detecting the presence of a VIS 204, the respective VDC 230 maygenerate an interrupt in a form of one or more logic level signals tothe MPC 220. If the presence of only one VIS 204 is detected, then theMPC. 220 instructs the MUX 210 to connect the port receiving the activeVIS 204 to the output of the MUX 210. The MPC 220, in turn, processesand displays the active VIS 204 using a display monitor (not shown inthis figure). If, on the other hand, two or more VDC 230 detect thepresence of two or more VIS 204, then the two or more VDC 230 maygenerate two or more interrupts to the MPC 220. Accordingly, the MPC 220may alert (i.e., prompt) a system user with a message on the displaymonitor to select one of the two or more VIS 204 for viewing. The usermay then respond to the MPC 220 by pressing one or more control buttons(located on the screen or elsewhere) or clicking a mouse. Upon selectinga VIS 204 to view, the MPC 220 may instruct the MUX 210 accordingly.

It is sometimes desirable to prompt the user to select a video port eachtime a new VIS 204 is detected by the respective VDC 230. For instance,if a user is viewing a VIS 204 a, and a video signal is detected at theVIS 204 c port, then the MPC 220 will prompt the user to select whetherto view the newly detected VIS 204 c or continue viewing VIS 204 a.Alternatively, if the user is already viewing a VIS 204, the MPC 220 mayoptionally be configured not to prompt the user to select a video porteven if another VIS 204 is newly detected. This option may allow theuser to view a video source without interruption due to the presence orarrival of another VIS 204.

Moreover, upon detecting the absence of one or more VIS 204, therespective one or more VDC 230 may generate one or more interrupts in aform of one or more logic level signals to the MPC 220. Consequently,the MPC 220 may notify the user with a message on the users displaymonitor. The message may comprise, among other things, the code or namewhich identifies one or more video sources whose absence is detected.The user may acknowledge such notification by pressing one or morecontrol buttons or clicking a mouse. The MPC 220 may notify the user ofthe absence of a VIS 204 port each time a new absence of a VIS 204 isdetected by the respective VDC 230. Alternatively, however, if the useris already viewing a VIS 204, the MPC 220 may optionally be configurednot to notify the user to select a video port even if the absence ofanother VIS 204 is newly detected. This option may allow the user toview a video source without interruption due to the absence ortermination of another VIS 204.

FIG. 3 is a flowchart describing the steps executed by the video system200. The process begins at step 300 when the video system 200 ispowered-up or initialized. At step 310, the VDC 230 monitors the arrivalor, if already present, termination of one or more video signals (i.e.,VIS 204) from one or more video sources. At step 320, the VDC 230determines whether one or more new VIS 204 are detected at an inputport. Hence, if one or more VIS 204 are already present, the VDC 230takes no affirmative action. The VDC 230 returns to the monitoring stepat 310. The duration of time between two consecutive monitoring stepsmay be determined and programmed as desired by the system operator. Onthe other hand, if the arrival of one or more new VIS 204 is detected atstep 310, then the process proceeds to step 330. At step 330, the VDC230 generates one or more interrupts to notify the MPC 220 of thepresence (or absence) of one or more VIS 230.

At step 340, the MPC 220 records the one or more interrupts anddetermines if more than one VIS 204 is detected. If the arrival of onlyone VIS 204 is detected, and no other VIS 204 are active, then the MPC220 may automatically display the only active video source at step 350.Alternatively, however, the system operator may desire to instruct thevideo system 200 to always prompt the user to select to view a VIS 204,even if only one VIS 204 is active. On the other hand, if the arrival ofmore than one new VIS 204 is detected, then the MPC 220 may prompt theuser to select the video source the user desires to view. Consequently,at step 370, the video system 200 displays the desired VIS 204 to theuser. The process terminates at step 380. In practice, unless instructedotherwise, the video system 200 returns to the monitoring step at 310and, hence, does not terminate.

FIG. 4 is a block diagram of one embodiment of the VDC 230 of the videosystem 200. It is worth noting that, depending on the technicalspecifications of the video system, there may be many variations of theVDC 230 which will appear obvious from the following description to onehaving ordinary skill in the art. In this description, an industrystandard architecture (ISA) based video system is used to implement theVDC 230. However, any other types of systems having an interrupt schememay be used including, without limitation, extended ISA (EISA) andperipheral component interconnect (PCI).

As shown in FIG. 4, the VDC 230 comprises one or more bandpass filters(BPF) 410 electrically connected to one or more video sources (not shownin this figure) supported by the video system 200. For instance, thevideo system may support TV broadcasting channels, vertical syncchannels, and many others. Hence, a BPF 410 a may be used to detectvideo signals in the very high frequency (VHF) range of about 30-300MHz. A BPF 410 b may be used to detect video signals in the ultra highfrequency (UHF) range of about 300-3000 MHz. A BPF 410 c may be used todetect video signals directly received in the range of 50-100 Hz.Typically, a video cassette recorder (VCR) provides an output on VHFchannels 3 and 4. Hence, a VCR output may be connected to a circuit witha VHF BPF (i.e., BPF 410 a). A satellite video signal may be in a MPEGformat and, hence, may be connected through a filter with a BPF coveringMPEG frequencies, i.e., 90(MPEG1)−64(MPEG4) kHz.

It is desirable to have the output signal of a BPF 410 conform to thelogical state levels recognized by the video system 200. For instance,if the video system is a 5-Volt based system (i.e., one that recognizes0 V as a low logical state and 5 V as the high logical state), it isdesirable to have the output of a BPF 410 be in the range of 0-5 volts.Moreover, the BPF 410 is selected so that, whenever there exists anyminimal video activity by a VIS 204, its output signal is able toactivate, drive, or trigger a subsequent component such as a transistor.Bandpass filters having lower and upper cutoff frequencies in variousranges of frequencies are known in the art.

The VDC 230 further comprises one or more interrupt generation circuits(IGC) 420 electrically connected to the one or more BFP 410. Upondetecting a VIS 204, the IGC 420 issues an interrupt signal to the MPC220 (FIG. 2). The IGC 420 may comprise a set of resistors and capacitorscoupled to a digital generation logic. Hence, the design of the IGC 420may be accomplished in a variety of ways. Moreover, the followingdescription is for an IGC 420 which detects and generates an interruptfor a single VIS 204. Hence, using other BPFs (e.g., BPF 410 b, 410 c,etc.), the following IGC 420 may be duplicated to detect and generate aninterrupt for virtually any desired number of VIS 204.

In one embodiment, the IGC 420 is a one-shot interrupt generator whichcomprises a resistor R1 421 connected to the base of a bipolarTransistor 422. The emitter of the Transistor 422 may be terminated byconnecting a resistor R2 423 in parallel with a capacitor C1 424 toground. The combination of these resistors, capacitor and transistorprovides a signal of logical state level 1 (i.e., high) after apredetermined period from the occurrence of a signal activity on theoutput of the BPF 410 a. The occurrence of signal activity is typicallyin response to detecting of a video signal VIS 204.

The voltage signal at the emitter of the Transistor 422 is connectedinto a first input of a NOR Gate 425. The output of the NOR Gate 425 isconnected to one end of a capacitor C2 426. The voltage signal at theoutput or, in this case, collector of the Transistor is connected to theother end of C2 426 via a resistor R3 427. The other end of C2 426 isfed into an inverter 428 whose output is fed back into a second input ofthe NOR Gate 425. Examples of the inverter 428 include the SN7405manufactured by TI. The output of the inverter 428 may be fed into a Jinput of a JK flip-flop (JKFF) 429. As is well known in the art, thecharacteristics equation of a JKFF 429 is Q(t+1)=JQ′+K′Q. In a JKFF 429the letter J is for “set” and the letter K is for “clear.” Examples ofthe JKFF 429 include the SN74F109 manufactured by TI. As noted above, inan ISA based video system, the JKFF 429 receives a clock pulse (CP)input from the ISA clock 432. The output Q′ (Q-not) of the JKFF 429 isconnected to another inverter 431 whose output is fed into the MPC 220(FIG. 2). The inverter 431 drives an interrupt line with an opencollector output in compliance with the ISA standard.

The operation of the various components of the VDC 230 is describedhereafter. When a VIS 204 is received by a BPF 410, the Transistor 422is triggered and thereby charges C1 424. When the voltage signal acrossC1 (i.e., emitter voltage) reaches a logical state of level 1, then R1421, NOR Gate 425, C2 426, and inverter 428 are activated to generate aninput into J of the JKFF 429. The JKFF 429 receives the output of theinverter 428 and produces an interrupt over the ISA bus to the MPC 220for action. Upon processing the interrupt by the MPC 220, the GPIO 240reads the status of each VIS 204 through its respective JKFF 424 andtransistor 422 connection. Once it reads the status of each VIS 204, theGPIO 240 resets the JKFF 424 through the K input. In case of more thanone VIS 204, the GPIO 240 may reset one or more JKFF 424 simultaneously.

It is desirable to have the values of C1 424 and R2 423 be selected sothat C1 424 maintains the logical state 1 despite and through momentarylapses in activity of the VIS 204. The duration of maintaining thelogical state 1 across C1 424 may be in the order of few seconds. Thisduration aids in preventing the generation of another independentinterrupt from an invariant video source, i.e., which has an essentiallyconstant VIS 204. A typical value for C1 may be in the range of about90-100 picofarads, and for R2 may be in the range of about 0.9-1 kOhms.

It is desirable to select values for C2 426 and R3 427 so that theinverter 428 outputs a pulse signal having a period equal to at leasttwice the period of the CP of the JKFF 429. The duration of at leasttwice the period of the CP ensures that the JKFF 429 captures a changein the logical state of the output signal of the inverter 428. Theone-shot aspect of the IGC 420 refers to the ability of the IGC 420 notto output another signal until the voltage level across C1 424 fallsbelow than and rises back to the logical state 1. Alternatively, aSchmitt trigger circuit (not shown in this figure) may be used to chargeC1 424 to generate this type of logical state output. The design andimplementation of a Schmitt trigger circuit is well known in the art.

If T is the duration of a one-shot pulse signal, C is a capacitance(i.e., C2 424), R is a resistor (i.e., R3 427), and Cf is the clockfrequency of CP, then T=0.69*R*C and R*C=2/(0.69*Cf). Hence, forexample, for a clock frequency of 33 MHz, then appropriate values areR3=910 Ohms, and C2=100 picofarads, thereby providing a pulse durationT=62.8 nanoseconds. It is desirable to have the clock pulse (i.e., CP)of the JKFF 429 be fast enough to ensure that the duration of theone-shot pulse signal terminates before the minimum interrupt responsetime of the video system. Having the one-shot pulse signal terminate inthis manner avoids the generation of spurious interrupts when the JKFF429 is reset.

FIG. 5 is an exemplary screen display indicating the presence of one ormore video signals in the video system of FIG. 2. As shown in FIG. 5,upon detecting the presence of a new VIS 204, the MPC 220 prompts theuser to select whether to view the new signal or maintain currentviewing status. The MPC 220 also prompts the user to switch to a controlpanel whereby the user may set default information such as selection ofa video source. In this embodiment, the user makes a selection by simplyclicking an appropriate button on the screen.

FIG. 6 is an exemplary screen display of a control panel of the videosystem 200. As shown in FIG. 6, a control panel allows a user to selecta default video input port (i.e., a video source). The number of inputports may be limited by the number of various video sources available tothe video system 200. In this embodiment, four video sources are shown:(1) Front S-Video; (2) Rear S-Video; (3) NTSC (RCA Jack); and (4) NTSC(BNC Jack). These video sources are provided to illustrate the kind andnature of video source selection and, hence, many other video sourcesmay be selected. Moreover, the control panel may provide several otherfunctions which a user may desire to control or set default valuesthereto.

In view of the foregoing, it will be appreciated that the inventionovercomes the long-standing need for a system and method for selecting adesired video input in accordance with the desire of a user. Theinvention may be embodied in other specific forms without departing fromits spirit or essential characteristics. The described embodiment is tobe considered in all aspects only as illustrative and not restrictive.The scope of the invention is, therefore, indicated by the appendedclaims rather than by the foregoing description. All changes which fallwithin the meaning and range of equivalency of the claims are to beembraced within their scope.

What is claimed is:
 1. A video system which displays at least one videosignal to a user, the system comprising: at least two video inputs, eachconnected to a different video signal source so as to receive videosignals therefrom; at least one detection circuit, wherein eachdetection circuit is connected to at least one of the video inputs suchthat activity related to at least two video signals is detected, andwherein the detection circuit communicates information about theactivity for processing; and a processing circuit, electrically coupledto at least one detection circuit, which receives the information aboutthe activity from the at least one detection circuit and, during displayof the at least one video signal, notifies the user of the activityrelated to the at least two video signals, including a video signalother than the video signal being displayed, so that the user mayinitiate action by the video system to display a user selected one ofthe video signals in response to the notification.
 2. The system asdefined in claim 1, wherein the detection circuit detects andcommunicates to the processing circuit information about arrival of theat least one video signal.
 3. The system as defined in claim 2, whereinthe detection circuit communicates to the processing circuit at leastone interrupt signal upon detecting the arrival of the at least onevideo signal.
 4. The system as defined in claim 1, wherein theprocessing circuit is configured to cause the display of the one of theat least one video signal.
 5. The system as defined in claim 1, whereinthe detection circuit comprises a band pass filter which is responsiveto the at least one video signal.
 6. A video system as defined in claim1, wherein the at least one detection circuit comprises at least twodetection circuits.
 7. A video system as defined in claim 1, wherein theprocessing circuit notifies the user of the activity by causing thevideo system to display a message.
 8. The video system of claim 7wherein the message comprises a menu presenting information as tosources of video signals present on the plurality of inputs so the usercan select one of the video signals for display.
 9. The video system ofclaim 7 wherein display of the at least one video signal is interruptedwhile the message is displayed.
 10. A video system which displays atleast one video signal to a user, the system comprising: a detectioncircuit which detects the arrival of and an activity related to the atleast one video signal, and communicates at least one interrupt signaland information about the arrival and the activity for processing; aprocessing circuit, electrically coupled to the detection circuit, whichreceives that at least one interrupt signal and the information aboutthe arrival and the activity from the detection circuit, and notifiesthe user of the activity related to the at least one video signal duringthe display of a video signal other than the at least one video signal;and a general purpose input/output unit which resets the interruptsignal after a predetermined period of time.
 11. A video display systemwhich displays at least one video signal to a user, the systemcomprising: at least two video inputs, each connected to a differentvideo signal source so as to receive video signals therefrom; at leastone detection circuit, wherein each circuit is connected to at least oneof the video inputs such that presence of at least two video signals isdetected via a plurality of video inputs, and wherein the detectioncircuit communicates at least one interrupt signal for processing; and aprocessor, electrically coupled to the at least one detection circuit,which receives the interrupt signal, determines which of the at leasttwo video signals is present and, during display of the at least onevideo signal, notifies the user to select one of the at least two videosignals, including a video signal other than the one being displayed,for display, wherein the processor notifies the user to select one ofthe at least two video signals by causing the video signal to display amessage, said message comprising a menu presenting information as tosources of the video signals present at the plurality of video inputs sothe user can select one of the video signals for display.
 12. The systemas defined in claim 11, wherein the processor executes the display of avideo signal in accordance with the user selection.
 13. A method ofdisplaying at least one video signal to a user, the method comprising:detecting the presence of a first video signal from a first source on afirst input, and a second video signal from a second source on a secondinput; communicating information about the detected video signals to aprocessor; during display of the first video signal, notifying the userof the detection of the second video signal so that the user can selectat least one of the first and second video signals for display, whereinnotifying the user of the detection comprises causing the video systemto display a message, said message comprising a menu presentinginformation as to sources of video signals present at the inputs so theuser can select at least one the first and second video signals fordisplay; and displaying a selected one of the first and second videosignals in response to a user input.
 14. The method as defined in claim13, wherein the act of communicating information includes the act ofsending at least one interrupt signal to the processor.
 15. The methodas defined in claim 13 further comprising the act of monitoring at leastone input port for the at least owe video signal.
 16. The method asdefined in claim 13, wherein the act of detecting an activity includesthe act of detecting arrival of the at least one video signal.
 17. Avideo system which displays at least one video signal to a user, thesystem comprising: means for detecting the presence of a first videosignal from a first source on a first input, and a second video signalfrom a second source on a second input; means, electrically coupled tothe detection means, for communicating information about the detectedvideo signals for processing; and means, electrically coupled to thecommunication means, for processing the information about the detectedvideo signals, wherein during display of the first video signal, theprocessing means notifies the user of the detection of the second videosignal so that the user may select at least one of the video signals andinitiate action by the video system to display the selected at least oneof the video signals in response to the notification, wherein the meansfor processing notifies the user of the detection by causing the videosignal to display a message, said message comprising a menu presentinginformation as to sources of video signals present at the inputs so theuser can select at least one of the video signals for display.
 18. Thesystem as defined in claim 17, wherein the detection means detects thearrival of the at least one video signal.
 19. A The system as defined inclaim 18, wherein the communication means communicates to the processingmeans at least one interrupt signal in response to the arrival of the atleast one video signal.
 20. The system as defined in claim 17, whereinthe user selects one of the at least one video signal for viewing. 21.The system as defined in claim 20, wherein the processing means isconfigured to cause the display of the one of the at least one videosignal.
 22. The system as defined in claim 17, wherein the detectionmeans comprises means for filtering signals, the filtering means beingresponsive to the at least one video signal.
 23. A program storagedevice storing instructions that when executed by a computer perform amethod of displaying at least one video signal to a user, the methodcomprising: detecting the presence of at least one of a first videosignal from a first source on a first input, and a second video signalfrom a second source on a second input; communicating information aboutthe detected video signals to a processor; during display of the firstvideo signal, notifying the user of the second video signal if detected,so that the user can select at least one of the first and second videosignals for display, wherein notifying the user comprises causingdisplay of a message, said message comprising a menu presentinginformation as to sources of the video signals present at the inputs sothe user can select at least one of the video signals for display; anddisplaying a selected one of the first and second video signals inresponse to a user input.
 24. The storage device as defined in claim 23,wherein the act of communicating information includes the act of sendingat least one interrupt signal to the processor.
 25. The storage deviceas defined in claim 23, wherein the method further comprises the act ofmonitoring at least one input port for the at least one video signal.26. The storage device as defined in claim 23, wherein the act ofdetecting an activity includes the act of detecting arrival of the atleast one video signal.
 27. A video system which displays at least onevideo signal to a user, the system comprising: a plurality of videoinputs, each input adapted to receive a corresponding video inputsignal; at least one video detection circuit, wherein the at least onevideo detection circuit detects video input signals from each of theplurality of video inputs; and a processing circuit, electricallycoupled to the at least one video detection circuit, the processingcircuit receiving information from the at least one detection circuitabout presence of video signals at the plurality of video inputs, and inresponse to receiving information about presence from at least onedetection circuit, notifies the user if the received informationindicates presence of at least two video input signals during thedisplay of the at least one video signal, wherein the processing circuitnotifies the user of the presence of at least two video signals bycausing the video system to display a message, said message comprising amenu presenting information as to sources of the video signals at theplurality of video inputs so the user can select one of the at least twovideo signals for display.
 28. A method of displaying at least one videosignal to a user, the method comprising: receiving signals at aplurality of inputs; monitoring the received signals for presence of aplurality of video signals; communicating information about the receivedsignals to a processor; and during display of a first video signal,notifying the user of presence of the plurality of video signals so thatthe user may select one of the plurality of video signals for display,wherein notifying the user of the presence of the plurality of videosignals comprises displaying a message, said message comprising a menupresenting information as to sources of the plurality of video signalspresent at the plurality of inputs so the user can select one of theplurality of video signals for display.